In some applications for small PMDC motors, the motors are inserted into a sub-assembly by a robot. The sub-assembly will comprise male power supply terminals which mate with female terminals on the motor. To ensure a good connection, the male terminal is gripped tightly using a strongly sprung female terminal. The female terminal must be displaced against the spring force by the male terminal as it is inserted and this can result in damage to the male terminal which may not be sensed by the robot when installing the motor.